PAA graft

Table 1 Root mean square area roughness of PAA grafts on Au/Si measured over a 5 x 5 jjim...

The uniformity of these hyperbranched PAA grafts on PE films was studied by forming derivatives with visible and fluorescent dyes. These hyperbranched films were modified by treating an activated 3-PAA/PE film with an amine terminated p-methyl red dye (MR) 9 or with a dansyl amine 10 to form MR/3-PAA/PE or dansyl/3-PAA/PE films, respectively. Visual inspection under a light or fluorescence microscope showed that the methyl red-labeled and fluorescently labeled films were uniform in color and fluorescence. The methyl red/3-PAA/PE film derivafive showed a responsive color change wifh change in pH. The MR labeled 3-PAA/PE film was red after immersion in an acidic ethanol solution and yellow after treatment with a basic ethanol solution. 

The chemistry and procedures for modification of the - CO2H groups of PAA hyperbranched grafts on PE powder were analogous to those used for PAA grafts on PE or PP films and wafers. For example, a 90% yield in ester formation was possible using acid-catalyzed Fisher esterification. Likewise, quantitative reduction (ethyl chloroformate activation, borane-dimethyl sulfide reduction) to hyperbranched poly(allyl alcohol)s and amidation all could be carried out using procedures like those used for PAA/Au surfaces. 

Fig. 23 Degree of swelling [H(JSmax) - f Diwl/f Diw for PAA (Mn = 4.8kDa) as a function of the PAA grafting density in the OB regime at pH equal to a 4, b 5.8, and c 10. (Reproduced with permission from [89])...

Poly( ethylene oxide)-block-poly (propylene oxide)-hZock-poly(ethylene oxide)-g-poly(acrylic acid) (PEO-fc-PPO-fc-PEO-g-PAA, Pluronic-PAA) graft copolymers were synthesized by free radical grafting copolymerization of acrylic acid monomers onto PEO-h-PPO-h-PEO (Pluronic F127) and the aqueous solution properties were characterized by Bromberg [133, 134]. Chiu et al. [135] reported on the micellization of (non-ionic) poly(stearyl methacrylate)-gra/f-poly(ethylene glycol) graft copolymers. 

Fig. 28 pH dependence of the aggregation behavior of PnBA-g-PAA graft copolymers in 0.1 M NaCl aqueous solution at room temperature ( ) nBAi34-g-(AA85)2 ( ) nBAios-g-... 

FIGURE 15.8 Release of FITC-dextran from membrane bags prepared from 50 wt% PAA grafted PVDF membranes into dissolution medium at pH 2.0 (filled circles) and pH 7.0 (open circles). (From Jarvinen, K., Akerman, S., Svarfvar, B., Tarvainen, T., Viinikka, P., and Paronen, P., Pharm. Res., 15, 802, 1998. With permission.)... 

Fig. 21 Degradation behavior of the 50 ppm solutions of PAA-grafted and ungrafted PEO in turbulent flow at Reynolds number Re = 75,000. The number in the legend indicates the molar percent of AA in PAA-grafted PEO. (Adopted with permission from Gryte...

The synthesis of core-shell magnetic nanoparticles from polyacrylic acid (PAA) graft copolymers containing side chains of PEO and PPO (Fig. 5) was demonstrated by Hatton et al. [102]. Using a mixture of the polymers at a temperature of 180°C, amine-terminated PEO and PPO were coupled onto the PAA via amidation. Super-paramagnetic polymer-coated nanoparticles were synthesized by the hydrolysis and condensation of Fe(II) and Fe(III) chloride salts in the presence of PPO- or PEO-modified PAA copolymers. The extraction of organic compounds from aqueous media towards the copolymer shell of hydrophobic PPO segments can be applied in the field of water purification. 

Fig. 5 Magnetic fluid synthesis in tin aqueous solution of PEO/PPO-PAA graft copolymer. Reprinted from [102] with permission...

Poly(acrylic acid) (PAA)-grafted CNTs, derived from the hydrolysis of fBA-grafted CNTs, could be applied as a charged nanosubstrate to coat polymer... 

Figure 5.12 Synthesis of PS-block-PAA-grafted MWCNTs by sequential ATRP of styrene and BA, followed by hydrolysis of FtBA block (top), a typical TEM image of PS-block-P/BA-grafted MWCNTs (bottom, left), and the samples of PS-grafted MWCNTs (A), PS-Z>-P/BA-grafted MWCNTs (B) and PS-Z -PAA-grafted MWCNTs (C) were placed in a mixed solvent of water (upper layer) and chloroform (bottom layer). Reprinted with permission from Kong et al ...

Another interesting application of membranes is shown in the work of JSrvinen and coworkers [13] who study drug release from pH and ionic strength responsive PAA grafted PVDF membrane bags in vitro. Square-shaped bags... 

Another study aiming to impart cell adhesion properties to PVA-C made use of a recently synthesized novel poly(amic acid) (PAA) polymer that has been shown to be cell compatible to form a PAA-grafted/crossIinked-PVA hydrogel (PAA-g/c-PVA). Functionalization of the PVA-C surface was accomplished by grafting of the PAA onto it to provide sites for cell attachment (Fig. 15). Successful endothelization with vascular endothelial cells was demonstrated (Fig. 16) [111]. 

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